Ecole d'Horlogerie Le Locle / J. Blanc, Les-Ponts-de-Martel, Case No. 1933, 50 mm, 101 g, circa 1933

A complex Swiss graduate's work with perpetual calendar - master piece
Case: 18K gold, polished, gold dome, pusher for separate switching of the months at "1". Dial: silvered, Arabic numerals, auxiliary seconds, three subsidiary chapter rings for indications of the weekdays, months and date, cobalt blue enamelled golden moon phase disc with gold moon and stars, window for leap year, blued Breguet hands. Movm.: bridge movement, rhodium-plated, ground, signed, wolfteeth winding wheels, finest steel parts for calendar, gold screw compensation balance, fine adjustment via threaded rod, counterpoised "Moustache" lever.

This extremely complicated and unique calendar mechanism has an integrated buffer system for the highly complex switching process and is operated through an eccentric wheel that applies an even pressure on the main control-lever and its tension spring. The switching operation for all indicators is activated every 24 hours. A central adjustment can be executed by pressing the pusher in the crown. A pusher at "1" adjusts the month in the calendar separately.